What Is Google Panda and Penguin?

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These have had the most effect on website's rankings since, still well into 2016. The Panda update is a filter that is designed to penalize “thin” or poor content from ranking well. Whereas Penguin is a filter that is designed to penalize websites that have bad link building techniques and keyword stuffing.
What does Google Panda do?
Google Panda is a major change to Google's search results ranking algorithm that was first released in February 2011. The change aimed to lower the rank of "low-quality sites" or "thin sites", in particular "content farms", and return higher-quality sites near the top of the search results.
How does Google Penguin work? The first thing you need to know is that Google Penguin only deals with incoming links into a website (also known as “backlinks”). In other words, it looks at which sites are linking to you, not which sites you are linking out to.